Seizures Flashcards
What are seizures?
Transient alterations in behaviour due to abnormally excessive and synchronous neuronal activity in the brain.
What is epilepsy?
Disorder characterized by frequent seizures.
What is symptomatc epilepsy?
Epilepsy caused by a brain injury.
What is asymptomatic epilepsy?
Epilepsy due to genetic predispositions.
How are seizures provoked?
Drugs and electrical stimulation?
What is surround inhibition?
The activity of one neuron will inhibit the activity of surrounding neurons to prevent overactivated synchronous activity and increase focused activity.
What are the three stages of a seizure?
Initiation, propagation, termination.
How are seizures initiated?
Sustained depolarization of neurons leads to calcium influx through NMDA receptors, causing high-frequency bursts of action potentials and hyper synchronization of neuronal propagation.
How are seizures propagated?
Extracellular potassium increases to prevent hyperpolarization. Accumulation of calcium in presynaptic cells enhances neurotransmitter release.
How are seizures terminated?
Mechanisms aren’t completely known, but relate to loss of ion gradients, loss of ATP, depletion of glutamate neurotransmitters, and activation of GABA.
What is status epilepticus?
Seizures lasting longer than five minutes, or when multiple seizures happen in less than five minutes.
What is the postical period?
Period after a seizure characterized by confusion, depression, fatigue, and possible psychosis.
What are the three classes of seizures?
- Focal seizures.
- Generalized seizures.
- Non-convulsive seizures.
What are simple focal seizures?
A focused seizure in which consciousness is not lost.
What are complex focal seizures?
A focused seizure in which consciousness is lost.